/* * Runtime locking correctness validator * * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra * * see Documentation/lockdep-design.txt for more details. */ #ifndef __LINUX_LOCKDEP_H #define __LINUX_LOCKDEP_H struct task_struct; struct lockdep_map; #ifdef CONFIG_LOCKDEP #include #include #include #include /* * Lock-class usage-state bits: */ enum lock_usage_bit { LOCK_USED = 0, LOCK_USED_IN_HARDIRQ, LOCK_USED_IN_SOFTIRQ, LOCK_ENABLED_SOFTIRQS, LOCK_ENABLED_HARDIRQS, LOCK_USED_IN_HARDIRQ_READ, LOCK_USED_IN_SOFTIRQ_READ, LOCK_ENABLED_SOFTIRQS_READ, LOCK_ENABLED_HARDIRQS_READ, LOCK_USAGE_STATES }; /* * Usage-state bitmasks: */ #define LOCKF_USED (1 #define LOCKF_USED_IN_HARDIRQ (1 #define LOCKF_USED_IN_SOFTIRQ (1 #define LOCKF_ENABLED_HARDIRQS (1 #define LOCKF_ENABLED_SOFTIRQS (1 #define LOCKF_ENABLED_IRQS (LOCKF_ENABLED_HARDIRQS | LOCKF_ENABLED_SOFTIRQS) #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ) #define LOCKF_USED_IN_HARDIRQ_READ (1 #define LOCKF_USED_IN_SOFTIRQ_READ (1 #define LOCKF_ENABLED_HARDIRQS_READ (1 #define LOCKF_ENABLED_SOFTIRQS_READ (1 #define LOCKF_ENABLED_IRQS_READ \ (LOCKF_ENABLED_HARDIRQS_READ | LOCKF_ENABLED_SOFTIRQS_READ) #define LOCKF_USED_IN_IRQ_READ \ (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ) #define MAX_LOCKDEP_SUBCLASSES 8UL /* * Lock-classes are keyed via unique addresses, by embedding the * lockclass-key into the kernel (or module) .data section. (For * static locks we use the lock address itself as the key.) */ struct lockdep_subclass_key { char __one_byte; } __attribute__ ((__packed__)); struct lock_class_key { struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES]; }; /* * The lock-class itself: */ struct lock_class { /* * class-hash: */ struct list_head hash_entry; /* * global list of all lock-classes: */ struct list_head lock_entry; struct lockdep_subclass_key *key; unsigned int subclass; /* * IRQ/softirq usage tracking bits: */ unsigned long usage_mask; struct stack_trace usage_traces[LOCK_USAGE_STATES]; /* * These fields represent a directed graph of lock dependencies, * to every node we attach a list of "forward" and a list of * "backward" graph nodes. */ struct list_head locks_after, locks_before; /* * Generation counter, when doing certain classes of graph walking, * to ensure that we check one node only once: */ unsigned int version; /* * Statistics counter: */ unsigned long ops; const char *name; int name_version; #ifdef CONFIG_LOCK_STAT unsigned long contention_point[4]; #endif }; #ifdef CONFIG_LOCK_STAT struct lock_time { s64 min; s64 max; s64 total; unsigned long nr; }; enum bounce_type { bounce_acquired_write, bounce_acquired_read, bounce_contended_write, bounce_contended_read, nr_bounce_types, bounce_acquired = bounce_acquired_write, bounce_contended = bounce_contended_write, }; struct lock_class_stats { unsigned long contention_point[4]; struct lock_time read_waittime; struct lock_time write_waittime; struct lock_time read_holdtime; struct lock_time write_holdtime; unsigned long bounces[nr_bounce_types]; }; struct lock_class_stats lock_stats(struct lock_class *class); void clear_lock_stats(struct lock_class *class); #endif /* * Map the lock object (the lock instance) to the lock-class object. * This is embedded into specific lock instances: */ struct lockdep_map { struct lock_class_key *key; struct lock_class *class_cache; const char *name; #ifdef CONFIG_LOCK_STAT int cpu; #endif }; /* * Every lock has a list of other locks that were taken after it. * We only grow the list, never remove from it: */ struct lock_list { struct list_head entry; struct lock_class *class; struct stack_trace trace; int distance; }; /* * We record lock dependency chains, so that we can cache them: */ struct lock_chain { struct list_head entry; u64 chain_key; }; struct held_lock { /* * One-way hash of the dependency chain up to this point. We * hash the hashes step by step as the dependency chain grows. * * We use it for dependency-caching and we skip detection * passes and dependency-updates if there is a cache-hit, so * it is absolutely critical for 100% coverage of the validator * to have a unique key value for every unique dependency path * that can occur in the system, to make a unique hash value * as likely as possible - hence the 64-bit width. * * The task struct holds the current hash value (initialized * with zero), here we store the previous hash value: */ u64 prev_chain_key; struct lock_class *class; unsigned long acquire_ip; struct lockdep_map *instance; #ifdef CONFIG_LOCK_STAT u64 waittime_stamp; u64 holdtime_stamp; #endif /* * The lock-stack is unified in that the lock chains of interrupt * contexts nest ontop of process context chains, but we 'separate' * the hashes by starting with 0 if we cross into an interrupt * context, and we also keep do not add cross-context lock * dependencies - the lock usage graph walking covers that area * anyway, and we'd just unnecessarily increase the number of * dependencies otherwise. [Note: hardirq and softirq contexts * are separated from each other too.] * * The following field is used to detect when we cross into an * interrupt context: */ int irq_context; int trylock; int read; int check; int hardirqs_off; }; /* * Initialization, self-test and debugging-output methods: */ extern void lockdep_init(void); extern void lockdep_info(void); extern void lockdep_reset(void); extern void lockdep_reset_lock(struct lockdep_map *lock); extern void lockdep_free_key_range(void *start, unsigned long size); extern void lockdep_sys_exit(void); extern void lockdep_off(void); extern void lockdep_on(void); /* * These methods are used by specific locking variants (spinlocks, * rwlocks, mutexes and rwsems) to pass init/acquire/release events * to lockdep: */ extern void lockdep_init_map(struct lockdep_map *lock, const char *name, struct lock_class_key *key, int subclass); /* * To initialize a lockdep_map statically use this macro. * Note that _name must not be NULL. */ #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ { .name = (_name), .key = (void *)(_key), } /* * Reinitialize a lock key - for cases where there is special locking or * special initialization of locks so that the validator gets the scope * of dependencies wrong: they are either too broad (they need a class-split) * or they are too narrow (they suffer from a false class-split): */ #define lockdep_set_class(lock, key) \ lockdep_init_map(&(lock)->dep_map, #key, key, 0) #define lockdep_set_class_and_name(lock, key, name) \ lockdep_init_map(&(lock)->dep_map, name, key, 0) #define lockdep_set_class_and_subclass(lock, key, sub) \ lockdep_init_map(&(lock)->dep_map, #key, key, sub) #define lockdep_set_subclass(lock, sub) \ lockdep_init_map(&(lock)->dep_map, #lock, \ (lock)->dep_map.key, sub) /* * To initialize a lockdep_map statically use this macro. * Note that _name must not be NULL. */ #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ { .name = (_name), .key = (void *)(_key), } /* * Acquire a lock. * * Values for "read": * * 0: exclusive (write) acquire * 1: read-acquire (no recursion allowed) * 2: read-acquire with same-instance recursion allowed * * Values for check: * * 0: disabled * 1: simple checks (freeing, held-at-exit-time, etc.) * 2: full validation */ extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass, int trylock, int read, int check, unsigned long ip); extern void lock_release(struct lockdep_map *lock, int nested, unsigned long ip); # define INIT_LOCKDEP .lockdep_recursion = 0, #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) #else /* !LOCKDEP */ static inline void lockdep_off(void) { } static inline void lockdep_on(void) { } # define lock_acquire(l, s, t, r, c, i) do { } while (0) # define lock_release(l, n, i) do { } while (0) # define lockdep_init() do { } while (0) # define lockdep_info() do { } while (0) # define lockdep_init_map(lock, name, key, sub) do { (void)(key); } while (0) # define lockdep_set_class(lock, key) do { (void)(key); } while (0) # define lockdep_set_class_and_name(lock, key, name) \ do { (void)(key); } while (0) #define lockdep_set_class_and_subclass(lock, key, sub) \ do { (void)(key); } while (0) #define lockdep_set_subclass(lock, sub) do { } while (0) # define INIT_LOCKDEP # define lockdep_reset() do { debug_locks = 1; } while (0) # define lockdep_free_key_range(start, size) do { } while (0) # define lockdep_sys_exit() do { } while (0) /* * The class key takes no space if lockdep is disabled: */ struct lock_class_key { }; #define lockdep_depth(tsk) (0) #endif /* !LOCKDEP */ #ifdef CONFIG_LOCK_STAT extern void lock_contended(struct lockdep_map *lock, unsigned long ip); extern void lock_acquired(struct lockdep_map *lock); #define LOCK_CONTENDED(_lock, try, lock) \ do { \ if (!try(_lock)) { \ lock_contended(&(_lock)->dep_map, _RET_IP_); \ lock(_lock); \ } \ lock_acquired(&(_lock)->dep_map); \ } while (0) #else /* CONFIG_LOCK_STAT */ #define lock_contended(lockdep_map, ip) do {} while (0) #define lock_acquired(lockdep_map) do {} while (0) #define LOCK_CONTENDED(_lock, try, lock) \ lock(_lock) #endif /* CONFIG_LOCK_STAT */ #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS) extern void early_init_irq_lock_class(void); #else static inline void early_init_irq_lock_class(void) { } #endif #ifdef CONFIG_TRACE_IRQFLAGS extern void early_boot_irqs_off(void); extern void early_boot_irqs_on(void); extern void print_irqtrace_events(struct task_struct *curr); #else static inline void early_boot_irqs_off(void) { } static inline void early_boot_irqs_on(void) { } static inline void print_irqtrace_events(struct task_struct *curr) { } #endif /* * For trivial one-depth nesting of a lock-class, the following * global define can be used. (Subsystems with multiple levels * of nesting should define their own lock-nesting subclasses.) */ #define SINGLE_DEPTH_NESTING 1 /* * Map the dependency ops to NOP or to real lockdep ops, depending * on the per lock-class debug mode: */ #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i) # else # define spin_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i) # endif # define spin_release(l, n, i) lock_release(l, n, i) #else # define spin_acquire(l, s, t, i) do { } while (0) # define spin_release(l, n, i) do { } while (0) #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i) # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 2, i) # else # define rwlock_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i) # define rwlock_acquire_read(l, s, t, i) lock_acquire(l, s, t, 2, 1, i) # endif # define rwlock_release(l, n, i) lock_release(l, n, i) #else # define rwlock_acquire(l, s, t, i) do { } while (0) # define rwlock_acquire_read(l, s, t, i) do { } while (0) # define rwlock_release(l, n, i) do { } while (0) #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i) # else # define mutex_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i) # endif # define mutex_release(l, n, i) lock_release(l, n, i) #else # define mutex_acquire(l, s, t, i) do { } while (0) # define mutex_release(l, n, i) do { } while (0) #endif #ifdef CONFIG_DEBUG_LOCK_ALLOC # ifdef CONFIG_PROVE_LOCKING # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 2, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 2, i) # else # define rwsem_acquire(l, s, t, i) lock_acquire(l, s, t, 0, 1, i) # define rwsem_acquire_read(l, s, t, i) lock_acquire(l, s, t, 1, 1, i) # endif # define rwsem_release(l, n, i) lock_release(l, n, i) #else # define rwsem_acquire(l, s, t, i) do { } while (0) # define rwsem_acquire_read(l, s, t, i) do { } while (0) # define rwsem_release(l, n, i) do { } while (0) #endif #endif /* __LINUX_LOCKDEP_H */
